Container base



FIG. 1 is an isometric view of a top and front side of an ornamental design for a container base;

FIG. 2 is a top plan view of the container base of FIG. 1;

FIG. 3 is a bottom plan view of the container base of FIG. 1; and,

FIG. 4 is an isometric view of a bottom and front side of the container base of FIG. 1.

The dash-dash-dash-dash lines are included for the purpose of illustrating portions of the container base that form no part of the claimed design.

The dot-dash broken lines in the drawings define the bounds of the claim and form no part thereof. 

CLAIM The ornamental design for a container base, as shown and described. 